It was another tiara moment for Kate Middleton on Tuesday evening! The 33-year-old stepped out wearing another dazzling tiara a little over a month after she wore the Queen Elizabeth's Lotus tiara for her first state banquet — but this time, she donned a headpiece favorite of the late Princess Diana.

The Duchess opted for the Cambridge Lover's Knot tiara for the annual Diplomatic Reception hosted by the Queen at Buckingham Palace.

The Duchess opted for the Cambridge Lover's Knot tiara for the Diplomatic Reception Photo: Getty Images

Kate appeared to be wearing the same bespoke Alexander McQueen evening gown that she wore to the same event two years ago. However this year, it was the stylish royal's intricate tiara that stole the show, as she made her way to the palace with husband Prince William. The mom-of-two has previously worn the tiara three times before.

William's mother received the dazzling headpiece as a wedding gift from the Queen in 1981. Because of its association with Diana, and of course because of its Cambridge name, this beautiful design seems very fitting for Kate to wear to the important event.

Princess Diana wore the pearl-and-diamond topper on many occasions after receiving it on loan from the Queen Photo: Getty Images

The masterpiece was created in 1914 for Queen Mary and features pearls suspended from diamond love knots. Diana, who favored the tiara, said it was so heavy it induced a headache and that she had to switch to her Spencer family tiara instead.

As a young woman, the Queen Mother often wore the Cambridge Lover's Knot tiara before handing it down to her youngest daughter, Princess Margaret.

Tuesday evening's white-tie Diplomatic Reception is the main ambassadorial social event of the year in London. Buckingham Palace states it "reflects the Queen’s importance in the country’s diplomatic relations" and all senior members of the royal family, who do not have prior engagements, will attend. The event is the largest reception held annually at Buckingham Palace, with more than 1,500 dignitaries invited from around 130 countries.